I'm all for people treating themselves now and then if they can afford it, especially if they're normally quite frugal, but this is just a plain black vest top, in bog-standard viscose blend, and I see no sense in spending that much money when you could get something virtually identical for far less.
If it were a statement piece, like an amazing dress that you couldn't get anywhere near on the high street, or conversely a perfectly fitting staple like tailored trousers or a coat that would last years, then i would say go for it. But this is just spending money for the sake of it.